Sure, but over the years there have also been a number of lost at sea
accidents where either the FDR or CVR were not recovered or were recovered
damaged. Dave Warren's original proposal was aimed squarely at that problem
and was for a foam cored blister pack with a simple wire spool recorder and
die pack, the concept being that it would be mounted on the external
fuselage (around the tail) and popped off in an explosion or impact induced
hull over-pressure.

>> > On 10 Mar 2014, at 22:17, Matthew Squair <mattsquair_at_xxxxxx
> >> > Absolutely, nothing is perfect. But would I prefer an alternate to> months of trawling the abyssal plain with a side scanning sonar? You> betcha. Especially if it's a very, very cheap alternative.>> In the last twenty years, there are just two cases of lost-at-sea I can> think of in which evidence from the hull was *not* required in addition to> FDR data to determine cause. There are five cases in which in-air> disintegration or burning, which are not identifiable from FDR data,> initiated the hull loss, and there is one further case in which physical> evidence was required to show there was no anomaly (that it was, in effect,> murder/suicide). Two against six isn't a persuasive ratio.>> I can go through the records to make this definitive rather than "I can> think of", if necessary.>> The result of a cost-benefit analysis, even for the past, let alone for> conceivable future cases, is not at all evident to me.>> PBL>> Prof. Peter Bernard Ladkin, University of Bielefeld and Causalis Limited>